Process for the manufacture of anhydrous beryllium fluoride free from oxide



March 4, 1941. ADAM OLI I 2,233,465

- PROCESS FOR MA ACTURE 0F ANHYDROUS BERYLLIUM F F FROM OXIDE Fil Jan. '7, I59 2 Sheets-Sheet 1 I 1710577 to):

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- March 4, 1941. c. ADAMOLI 46 PROCESS FOR THE MANUFACTURE OF ANHYDROUS BERYLLIUM FLUORIDE FREE FROM OXIDE Filed Jam. 7, 1939 2 Sheets-Sheet 2 I l V flflfl Patented Mar. 4, 1941 PATENT OFFICE:

PROCESS FOR THE MANUFACTURE OF ANHYDROUS BERYLLIUM FLUORIDE FREE, FROM OXIDE Carlo 'Adamoli, Milan, Italy, assignor to Perosa Corporation, Wilmington, DeL, a corporation of Delaware Application January 7, 1939, Serial No. 249,828 In Italy January 10, 1938 i 10 Claims.

Presently only two methods are known for producing, in the laboratory, anhydrous beryllium fluoride which is free from oxide and which corresponds to the formula BeFz (Lebeau, Annales de Chimie et de Physique 1869-4- (7) 484;

comptes-rendus Acadmie des Sciences (Paris) 1898 (126) 1418; Gmelins Handbuch, Beryllium System Numercer 26 p. 105)). These two methods have already received applications in the art which apparently considerably differ from anotherand one of which consists in causing gaseous hydrofluoric acid to react'at a temperature between 500 and 750 C. on beryllium oxide, more particularly in the form of dry hydroxide, ac' cording to the reaction BeO+2 'I-IF=BeF'2+I-I2O, while the other consists in forming double ammonium beryllium fluoride in the 'dry state through the reaction of acid ammonium fluoride on beryllium oxide or beryllium hydrate, and

then in distilling the ammonium fluoride accordsaiification water which ordinarily causes the hydrolysis of the beryllium fluoride and determines the formation of the beryllium oxide which is generally contained in the known prodnot which is improperly designated under the name of beryllium fluoride, while it is, in fact, a basic product of various compositions. Now, while they well permit to avoid the hydrolysis of the beryllium fluoride and to obtain this salt in an anhydrous condition, the said methods offer, again, certain technical disadvantages resulting, in one case, in the difficulty of using the gaseous hydrofluoric acid at a high temperature and of working on masses of a large volume and, in the second case, in the double operation consisting in'producing the dry ammonium fluoride for subsequently distilling it while using a quantity of fluorine which is double of that which corresponds carbonate, the quantity of ammonium fluoride which is used being such that it substantially corresponds to that which is theoretically necessary for the sole conversion of the beryllium into beryllium fluoride; When starting, for instance, from beryllium oxide and neutral ammonium fluoride, the reaction which character'- izes the process according to the invention may then be written as follows:

the ammonia and the water being eliminated as they are formed by the aspiration of the apparatus which serves to maintain the reactional medium under the vacuum.

In order to insure the complete fiuorination of the beryllium, it is advantageous to work with a slight excess of ammonium fluoride of less than of the stoichiometric quantity which is necessary for efiectuating the above mentioned reaction, or with the addition of a corresponding quantity of acid ammonium fluoride.

It is also advantageous to effectuate thereaction in two successive steps in different conditions of temperature, the first step being efiectuated at a temperature which is preferably less than 100 C. and until the escape of ammonia practically ceases, while the second step begins immediately after the firstand is effectuated at a higher temperature, preferably between 200 and 250 C. and preferably in the presence of a current of dry inert gas. It may be expedient, for preventing any possible losses in the apparatus, to introduce a small quantity of dry hydrofluoric acid simultaneously with this dry gas.

The invention provides more particularly; a form of execution in a cycle of the above defined process, according to which the intimate mixture of the neutral or acid ammonium fluoride with the oxygenated compound of the beryllium and the reaction between these agents are effectuated in closed heated vessels, while preferably fractionating the heating in two .ormore steps corresponding toincreasing temperatures condi ditions up to a maximum of 250 C., the ammonia which has been formed in a gaseous condition as well as the water which is present and that which forms during the reaction being removed from the said vessels bymeans of a suitable vacuum pump, the ammonium fluoride being re-formed from the collected ammonia, as, for

instance, bycausing the latter to' pass into a solution of hydrofluoric acid or, preferably, into an already saturated acid solution of ammonium fluoride, the fresh salt which is formed, then precipitating immediately. I

As shown in this example, the apparatus com prises a mixer I formed of a sloping cylinder in which rotates a propeller 2 which can be driven by a suitable drive (not shown). In its upper part the mixer is provided With a conduit 3 with a tight closure 3a for the introduction of the charge, and inits lower part it is provided with a conduit 4 which permits of the passage of the 1 material which has been treated into a second mixer 5. This latter is also formed of a sloping cylinder in which a propeller B rotates in a contrary direction fromv that of thepropeller 2. At the lower part of the mixer 5 there is provided a discharging device I for removing the beryllium fluoride which has been formed. Both mixers I and 5 are located in a drying oven 8 with two difierent temperature conditions, one of 80 0., for instance, for the operation in the mixer I and the other of 250 C. for the operation in the mixer 5.

At suitable places, for instance on the conduits 3 and 4, are connected conduits 8, 9a leading to the" inner space of -a :rotating" barrel. or drum I which contains a solution of hydrofluoric acid arriving by a pipe Ila from a recipient II and which, preferably,is saturated with ammonium fluoride but maintained acid for insuring the fluorination of the ammonia which has been removed from the mixer I, as will be explained hereinafter. The drum I0 is provided with filtering vanes l2 adapted for depositating the crystallized ammonium fluoride into a vat I3 secured on the axial support Illa of the drum;

The inner space of the drum I0'is connected, on the other hand, by means of a conduit I4,

with a drying tower l which is connected, by

meansof a conduit l6,.with the suction side of a pump I! the discharge of which is connected .by means of conduits I8, I8a with the mixer -5 for the introduction of a neutral gas into'the latter. The operation of this apparatus is as follows. 100 kg. of beryllium hydrate Be(AH) z with 60% of BeOin a granulated form are introduced, for

instance, into the mixer I with 178 kg. of neutral ammonium fluoride .(which quantity can be, if

desired, increased up to 185, kg.) or with 137 kg.

duced into the mixer I and which are intimately.

mixed by the propeller 2 pass progressively into the mixer 5, while-the ammonia and the steam which'escape under the action of the heating are drawn in by the vacuum pump together with the neutral gas which is introduced into the mixer 5 and are derived by the conduits 9,. 9a into the absorption apparatus IiL, The ammonia. is further removed up to the quantity which must be theoretically obtained. Finally about 112 kg. of 1 ammoniurnfluoride which has been depositated into the vat I3 by 'thefiltering vanes I2 are removed from the absorption apparatus III which contains the mother liquors from the preceding operations. The-neutral gas which has been recuperated in the drum I0 is dried in the tower I5 and taken again by the pump I1 whereafter it is re-introduced into the mixer 5.

' The process of the present application is a modification of the process described and claimed in my Patent No. 2,173,290, granted September What I claim is:

1. A process for the manufacture of anhydrous beryllium fluoride free from oxide, which consists in causing a compound of the group consisting of-ammonium fluoride and ammonium acid fluoride to'act in vacuo and in the hot state on an oxygenated beryllium compound belonging to thegroup consisting of the oxide, the hydrate and the carbonate of beryllium, in a dry state, the proportion-of ammonium fluoride which is used substantially corresponding to that which is theo- 'retically necessary for forming only beryllium fluoride. r

2. A process for the manufacture of anhydrous beryllium fluoride free from oxide, which con: sistsin causing neutral ammonium fluoride to act in vacuo and in the hot'stateon an oxygenated beryllium compound belonging to the group consisting of the oxide, the hydrate and the carbonate of beryllium, in a dry state, the proportion of neutral ammonium fluoride which is used substantially corresponding to. that which is, theoretically necessary for forming only beryllium fluoride. I

3. A process for the manufacture of anhydrous beryllium fluoride free from oxide, which consists incausing acid ammonium fluoride to act in vacuo and in the hot state on an oxygenated.

bonate of bery11ium,}in a dry state, the proportion of ammonium fluoride which is used not exceeding by more than 5% that which is theoreti cally necessary for forming only beryllium fluo-' ride.

5. A process for the manufacture of anhydrous beryllium fluoride free from oxide, which con-. sists in causing to actin a hot state and in vacuo on an oxygenated beryllium compound belonging to the group consisting of the oxide, the hydrate' and the carbonate of beryllium in, a, dry

state, ammonium fluoride in a quantitywhich substantially corresponds to that which is theeretically necessary for forming only beryllium fluoride, and in removing the ammonia and the water vapour from the, reactional medium as they are formed.

6. ,A process for the manufacture of anhydrous beryllium fluoride free from oxide, which consists in causing to act in a hot state ,and in vacuo.

on an oxygenated beryllium compound belong ing to the group consisting of the oxide, 'the hy-- drate and. the carbonate of beryllium, in a dry state, ammonium fluoridein a quantity which 50 sisting of the oxide, the hydrate and the carsubstantially corresponds to that which is theoretically necessary for forming only beryllium fluoride, in introducing a dry inert gas into the reactional medium and in removing from the said reactional medium the ammonia and the water vapour as they are formed simultaneously with the inert gas.

7. A process for the manufacture of anhydrous beryllium fluoride free from oxide, which consists in causing to act in a hot state and in vacuo on an oxygenated beryllium compound belonging to the group consisting of the oxide, the hydrate and the carbonate of beryllium in a dry state, ammonium fluoride in a quantity which substantially corresponds to that which is theoretically necessary for forming only beryllium fluoride, in introducing a dry inert gas into the reactional medium with the addition of a small quantity of dry gaseous hydrofluoric acid and in removing from the said reactional medium the ammonia and the water vapour as they are formed simultaneously with the inert gas.

8. A process for the manufacture of anhydrous beryllium fluoride free from oxide, which consists in mixing an oxygenated beryllium compound belonging to the group consisting of the oxide, the hydrate and the carbonate of beryllium in a dry state and ammonium fluoride in a proportion which substantially corresponds to that which is theoretically necessary for forming only beryllium fluoride, in heating this mixture in vacuo up to a temperature of less than 100 C. until the escape of ammonia practically ceases and then to a temperature between 200 and 250 C., in introducing a dry inert gas into the reactional medium during the second step of the heating, and in removing from the said reactional medium the ammonia and the aqueous vapor as they are formed as well as the inert gas.

9. A process for the manufacture of anhydrous beryllium fluoride free from oxide, which consists in mixing an oxygenated beryllium compound belonging to the group consisting of the oxide, the hydrate and the carbonate of beryllium in a dry state and ammonium fluoride in a proportion which substantially corresponds to that which is theoretically necessary for forming only beryllium fluoride, in heating this mixture in vacuo up to a temperature of less than 100 C. until the escape of ammonia practically ceases and then to a temperature between 200 and 250 C., in introducing a dry inert gas into the reactional medium during the second step of the heating, in removing from the said reactional medium the ammonia and the aqueous vapor as they are formed as well as the inert gas and in causing the removed ammonia to pass into a solution of hydrofluoric acid in order to re-form the ammonium fluoride used in the process.

10. A process for the manufacture of anhydrous beryllium fluoride free from oxide, which consists in mixing an oxygenated beryllium compound belonging to the group consisting of the oxide, the hydrate and the carbonate of beryllium in a dry state and ammonium fluoride in a proportion which substantially corresponds to that which is theoretically necessary for forming only beryllium fluoride, in heating this mixture in vacuo up to a temperature of less than 100 C. until the escape of ammonia practically ceases and then to a temperature between 200 and 250 0., in introducing a dry inert gas into the reactional medium during the second step of the heating, in removing from the said reactional medium the ammonia and the aqueous vapor as they are formed as well as the inert gas, in causing the removed ammonia to pass into a solution of hydrofluoric acid saturated with ammonium fluoride for re-forming ammonium fluoride and collecting the latter in a crystalline form, and returning it to the process to treat a further quantity of oxygenated beryllium compound.

CARLO ADAMOLI. 

